Within the field of automatic horizontal packaging machines, the use of carrousels, chain conveyors and such like are known about. They are used to transport the tools designed to secure containers during the manufacturing process.
In general, a simultaneous, forwards movement is transmitted to these tools, which may be either continuous or intermittent. The packaging chain is therefore often referred to as a container train, given that all the containers are moved in unison at the same forwards moving rhythm, set by the rotation of the carrousel or the movement of the chain or continuous conveyor.
Traditionally, securing tools describe a closed, horizontal trajectory comprising two straight sections, one of which is operational and along the length of which the containers are secured and transported for handling, filling and subsequent closure in respective work stations and another return section, along the length of which the tools travel empty.
This kind of machine has certain limitations, which have been resolved in various ways.
Firstly, there is the limitation that unwanted inertia occurs, especially when the product to be packaged is a liquid. This inertia occurs each time the containers are held in a work station and when the transport movement towards a subsequent station starts up.
Inertia causes the product inside the containers to move and has a negative impact on the productivity of the machines, given that it prevents high transportation velocities involving more abrupt accelerations and decelerations from being applied to the containers, thus causing the product to come out of the upper portion of the containers.
In order to compensate for the limitation of not being able to make quick transitions between stations, productivity often tends to be increased by doubling the number of work stations, so that the operations to be carried out on the containers may go ahead in two consecutive containers travelling on the container train at the same time. Those machines that employ this solution, often referred to as duplex machines, deliver two finished containers in each forwards moving cycle. Nevertheless, they present the limitation of being larger, thereby impacting cost.
Patent document EP 2522584 describes an alternative solution, employing a carrousel comprising a guide, upon which a number of carts carrying the tools for securing the containers slide. In this machine, each cart carries a tool for securing two containers, whilst they are meanwhile transported in parallel along the external side of the guide. This makes it possible to double the productivity of the machine, without it being necessary to increase the length of the straight operational section of the carrousel, maintaining the forwards moving velocity of the machine, despite the fact that the required length of the tools for securing more than one container would generate other kinds of problems, owing to the weight of the containers being suspended when they are full or the reduction in available space for the filling and soldering mechanisms to be able to operate on the two containers at the same time as they are so close to one another. The machine also has a built in system that makes it possible to reduce the number of tools, without affecting the number of containers that the machine is capable of transporting at the same time along the straight operational section. This system is designed to uncouple the tools from the transportation system, which pulls them along the length of the straight operational section, in order to be transported by different means and at greater velocity along the length of at least the straight return section.
More recently, deriving benefit from innovative transportation systems that make it possible to control and operate mobile elements that are mounted to and may be moved along the length of a track individually, the company KHS USA Inc. shared knowledge of a machine model that serves as a substitute for the traditional mechanical drive carrousel for transporting the carts carrying the securing tools with a set of motor elements that may be operated independently, in order to move along the length of a track, which, just like the carrousel, determines a closed, horizontal route for said motor elements, the movement of which may be controlled individually, by means of employing a magnetic field. In this machine, each motor element carries a tool that works alongside the tool of an adjacent motor element in order to secure a corresponding container between the two, the same being arranged on the external side of the track and being transported along the length of a straight section of the same. Advantageously, not only may the motor elements move along the length of a return section of the track at greater velocity than along the length of the operational section, as in the proposal set out in EP 2522584, it is also no longer mechanically necessary to move all the containers along the operational section in the same way and in unison. In other words, it is no longer necessarily a container train but rather, each container may be moved and/or held independently from the others.
Both simple and dual versions of the machine described above, which applies this new transportation system, are known about, i.e., versions capable of transporting 1 or 2 bags lined up in each machine cycle, respectively.
The use of this kind of transportation system with movable platforms that may be easily positioned, may be put in different positions quickly and accurately by means of electromagnetic energy and may be configured easily. However, although they are suitable for transporting bags, the fact that they are new makes them very expensive.
Therefore, in order to save on costs, the machine model described above does not employ the magnetic field effect to propel the motor elements along the straight return section, thus saving on components and electromagnetic field generation control systems, which would need to build the track along the length of said straight return section, in order to magnetically propel the motor elements.
An object of the present invention is an alternative device to those known about, which makes it possible to increase the productivity of a horizontal packaging machine for flexible containers, thus avoiding the limitations presented by known devices.
According to another object of the invention, in addition to making it possible to increase the machine's productivity, thus avoiding the limitations of the solution of suspending two containers using the same tool, as described in patent document EP 2522584, it is also desirable for the device to be capable of increasing the transportation rhythm, i.e. of increasing the number of cycles per minute.